WordNet sense 1 (a district that is reserved for particular purpose):

reserve, reserve

WordNet sense 2 (a statement that limits or restricts some claim):

qualification

WordNet sense 3 (an unstated doubt that prevents you from accepting something wholeheartedly):

mental reservation, arriere pensee

WordNet sense 4 (the act of reserving (a place or passage) or engaging the services of (a person or group)):

booking